The broad aim of the research is to clarify the relations between gonadal hormones and reproductive behavior by analyzing sex-typical responses of ring doves. Male and female doves both participate in all aspects of reproduction and yet the hormonal mechanisms involved differ in the sexes. Research along three distinct lines is proposed: (1) androgens during the cycle, (2) diurnal cycles in incubation, (3) the study of feral doves. After pairing there occurs in the male dove a rise in plasma androgens which lasts 3-5 days. The stimulus producing this change in androgens and the physiological and behavior function will be studied. During the 15 day incubation period the parent ring doves take turns incubating their eggs. Most pairs establish a regular pattern with the male sitting for a block of time during the middle of the day and the female sitting the rest of the time. In a series of experiments stimulus and hormonal factors which produce sex differences in the timing of incubation are explored. Field studies on feral ring doves will be carried out to (1) compare the behavior of caged versus free animals and (2) to clarify the function of behaviors seen in the lab by examining the context in which they occur. BIBLIOGRAPHIC REFERENCES: Silver, R. and Barbiere C. (1977) Readiness to court and to incubate during the reproductive cycle of the ring dove. Horm. Behav. 8, 8-21. Cheng, M.F., and Silver, R. (1975) Estrogen-progesterone regulation of nestbuilding and incubation behavior of female ring doves (Streptopelia risoria) J. Comp. Physiol. Psychol. 88, 256-263.